@Stalkerman I mean, isn't it always in isekai? Random Japanese citizen X gets summoned while he's trying to head to the convenience store or whatever, "Oh hey, sorry to bother you but you have to work for us now. Go save our world."
That aside though, the context here seems to sort of imply that that summoning is possibly more like the Fate series when these guys summoned the elf or that vampire chick? The elf mentioned how they had disturbed his slumber or something, and the vampire was summoned to maintain her own family's castle they had already "summoned," but she wasn't immediately like "So it was YOU! My castle just disappeared, now I know why." So both her and the castle might be something like legendary figures from the past in either this world or another one? Isekai and all, if he can get yeeted here from Japan, I don't suppose anyone else doing so from elsewhere is off the table.